Delta sigma (ΔΣ or DS) modulation is a type of analog-to-digital (ADC) or digital-to-analog (DAC) conversion. The principle of ΔΣ modulation is typically to make evaluations of the input signal, to measure any error, integrate the error signal and then filter out out-of-band quantization or noise. Some ΔΣ modulators convert an analog input signal to a digital pulse string having an average amplitude over time proportional to the analog input. ΔΣ modulation provides for high accuracy and wide dynamic range as compared to other delta modulation techniques. ΔΣ modulation is sometimes referred to as an oversampled converter architecture which is immune from some undesirable second order effects of delta modulation.
A ΔΣ modulator generally comprises one or more integrators for an input signal, which are fed into a quantizer, the output of which is the output of the ΔΣ quantizer. The output is also fed through a digital to analog converter (DAC) in a feedback loop to the integrators.
As with many electronic circuits and components, the behavior of ΔΣ modulators may be sensitive to variations in temperature. Semiconductor and other materials have an inherent internal resistance and generate heat. This resistance is also subject to change with temperature, and may actually cause some internal heating in some applications.